/* $OpenBSD: kexgex.c,v 1.27 2006/08/03 03:34:42 deraadt Exp $ */
/*
 * Copyright (c) 2000 Niels Provos.  All rights reserved.
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>

#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/crypto.h>

#include "xmalloc.h"
#include "ssh2.h"
#include "buffer.h"
#include "packet.h"
#include "compat.h"
#include "cipher.h"
#include "key.h"
#include "kex.h"
#include "log.h"
#include "mac.h"
#include "match.h"
#include "dispatch.h"
#include "monitor.h"
#include "roaming.h"
#include "includes.h"

#include <sys/types.h>

#include <openssl/evp.h>
#include <signal.h>

#include "buffer.h"
#include "key.h"
#include "cipher.h"
#include "kex.h"
#include "ssh2.h"
#define DEBUG_KEXDH
#define DEBUG_KEX

void
kexgex_hash(
    const EVP_MD *evp_md,
    char *client_version_string,
    char *server_version_string,
    char *ckexinit, int ckexinitlen,
    char *skexinit, int skexinitlen,
    u_char *serverhostkeyblob, int sbloblen,
    int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
    BIGNUM *client_dh_pub,
    BIGNUM *server_dh_pub,
    BIGNUM *shared_secret,
    u_char **hash, u_int *hashlen)
{
	Buffer b, b1, dBuffer;
	static u_char digest[EVP_MAX_MD_SIZE];
	EVP_MD_CTX md;


	buffer_init(&b);
	buffer_init(&b1);

	buffer_put_cstring(&b, client_version_string);

	buffer_put_cstring(&b1, client_version_string);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);

	buffer_put_cstring(&b, server_version_string);

	buffer_put_cstring(&b1, server_version_string);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);


	/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
	buffer_put_int(&b, ckexinitlen+1);
	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	buffer_append(&b, ckexinit, ckexinitlen);


	buffer_put_int(&b1, ckexinitlen+1);
	buffer_put_char(&b1, SSH2_MSG_KEXINIT);
	buffer_append(&b1, ckexinit, ckexinitlen);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);
	
	

	buffer_put_int(&b, skexinitlen+1);
	buffer_put_char(&b, SSH2_MSG_KEXINIT);
	buffer_append(&b, skexinit, skexinitlen);

	buffer_put_int(&b1, skexinitlen+1);
	buffer_put_char(&b1, SSH2_MSG_KEXINIT);
	buffer_append(&b1, skexinit, skexinitlen);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);


	buffer_put_string(&b, serverhostkeyblob, sbloblen);

	buffer_put_string(&b1, serverhostkeyblob, sbloblen);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);

	if (min == -1 || max == -1)
		buffer_put_int(&b, wantbits);
	else {
		buffer_put_int(&b, min);
		buffer_put_int(&b, wantbits);
		buffer_put_int(&b, max);
	}

	buffer_put_int(&b1, min);
	buffer_put_int(&b1, wantbits);
	buffer_put_int(&b1, max);

	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);


	buffer_put_bignum2(&b, prime);
	buffer_put_bignum2(&b1, prime);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);
	buffer_put_bignum2(&b, gen);
	buffer_put_bignum2(&b1, gen);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);
	buffer_put_bignum2(&b, client_dh_pub);
	buffer_put_bignum2(&b1, client_dh_pub);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);
	buffer_put_bignum2(&b, server_dh_pub);
	buffer_put_bignum2(&b1, server_dh_pub);
	buffer_dump(&b1);
	buffer_free(&b1);
	buffer_init(&b1);
	buffer_put_bignum2(&b, shared_secret);
	buffer_put_bignum2(&b1, shared_secret);
	buffer_dump(&b1);
	buffer_free(&b1);
#ifdef DEBUG_KEXDH
	buffer_dump(&b);
#endif

	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	EVP_DigestFinal(&md, digest, NULL);

	buffer_free(&b);
	*hash = digest;
	*hashlen = EVP_MD_size(evp_md);
#ifdef DEBUG_KEX
	int ln = strlen(digest);
	dump_digest("digest", digest, ln);
#endif

}


void
dump_digest(char *msg, u_char *digest, int len)
{
	int i;

	fprintf(stderr, "%s\n", msg);
	for (i = 0; i < len; i++) {
		fprintf(stderr, "%02x", digest[i]);
		if (i%32 == 31)
			fprintf(stderr, "\n");
		else if (i%8 == 7)
			fprintf(stderr, " ");
	}
	fprintf(stderr, "\n");
}

